The invention relates to a parking lock device of a gearbox.
The relevant legislation stipulates that a parking lock device for dual clutch transmissions with a torque converter reliably and positively stops in the parking position on a hill that has a slope of up to 30%. For this purpose the prior art usually employs a parking lock device, wherein a parking gearwheel, which is securely mounted on the shaft of the gearbox, has recesses incorporated on the outside diameter. When parking, a pawl engages with these recesses and braces the gearbox against the housing. One drawback lies in the fact that the parking gearwheel is always entrained in rotation, thereby incurring losses. Furthermore, there is a high installation space requirement.
The object of the present invention is to propose a parking lock device that overcomes the drawbacks of the prior art.
The invention achieves this engineering object by the fact that at least one gearbox shaft is provided; that at least one gearbox housing is provided; that at least one locking ring is provided, wherein the locking ring can be displaced axially along the gearbox shaft, and wherein the gearbox shaft and the locking ring are arranged relative to one another in such a way that they coaxially surround one another; that at least one control ring is provided, wherein the control ring can be axially displaced relative to the locking ring and relative to the gearbox shaft; that the control ring and the locking ring are arranged relative to one another in such a way that they coaxially surround one another; that at least one movement of the control ring relative to the locking ring axially along the gearbox shaft causes an axial movement of the locking ring axially along the gearbox shaft, wherein the control ring displaces directly or offset in time the locking ring in an activated state axially along the gearbox shaft to a predetermined axial position along the gearbox shaft; that at least the gearbox shaft, the gearbox housing and the locking ring are designed and adapted to one another in such a way that at least in an activated state of the locking ring there is a positive engagement at least between the gearbox shaft, the gearbox housing and the locking ring. As a result, in the event that the parking lock device is engaged or more specifically is activated, a locking ring, which can be moved on the shaft of the gearbox, is displaced axially along the gearbox shaft and then facilitates a positive engagement between the gearbox shaft and the gearbox housing. Owing to this positive engagement, the gearbox shaft is fixed directly in relation to the gearbox housing and, in so doing, is locked. Between the movement of the control ring and the locking ring there can be, if desired, a time offset.
One embodiment of the invention includes that in at least one axial position relative to the gearbox shaft the locking ring is mounted in a rotationally rigid manner in relation to the gearbox shaft. Thus, the locking ring is guided in an outer contour of the gearbox shaft, for example, by an inner contour; or it moves into such a rotationally rigid, but axially movable guide upon activation of the parking lock device.
One embodiment of the invention provides that the gearbox housing has an interior space; and that the locking ring and/or the control ring is/are arranged outside the interior space. This embodiment can reduce the installation space of the housing.
One embodiment of the invention includes that the gearbox shaft, the gearbox housing, the control ring and the locking ring are designed and adapted to one another in such a way that in an activated state of the locking ring there is a positive engagement between the gearbox shaft, the gearbox housing, the control ring and the locking ring. In this embodiment the locking ring and the control ring accomplish together that a positive engagement is produced.
One embodiment of the invention provides that at least one spring element is arranged between the control ring and the locking ring. Such a spring element enables the control ring to move the locking ring.
One embodiment of the invention includes that the gearbox shaft has at least one outer contour; that the locking ring has at least one inner contour; and that the outer contour and the inner contour are adapted to one another. As a result, the contours are designed in such a way that the result will be a jamming between the locking ring and the gearbox shaft, or more specifically that the locking ring is guided or rather is mounted on the shaft of the gearbox in such a way that it is rotationally rigid in the radial direction.
One embodiment of the invention provides that the gearbox shaft is mounted in the gearbox housing by a shaft bearing.
One embodiment of the invention includes that a sealing ring is provided for the purpose of sealing off between the gearbox shaft and the gearbox housing.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of one or more preferred embodiments when considered in conjunction with the accompanying drawings.